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array.sort() being ignored in a for... in loop

I have an array whihc I have put a sort on, when I sue a for in loop to loop through the array, it acts as if the array hadn't been sorted. I noticed that using a regular for loop solves this problem, however, however I need this to work with the for in loop. I am aware that a for in will go through an array in reverse order, however this isn't the issue.

Here is the code greatly simplified code, and below, the results of the traces

Many thanks for helping solve this problem

function layout() {
      var cats = ["40artist", "30still", "50fashion"];
      trace("---- Part 1: "+cats);
      cats.sort();
      trace("---- Part 2: "+cats+"\n");
      for (var i in cats) {
            trace("---- Part 3: "+cats[i]);
      }
      trace("\n---- Part 4: "+cats+"\n");
}

layout();


---- Part 1: 40artist,30still,50fashion
---- Part 2: 30still,40artist,50fashion

---- Part 3: 40artist
---- Part 3: 30still
---- Part 3: 50fashion

---- Part 4: 30still,40artist,50fashion

0
cursive
Asked:
cursive
  • 2
1 Solution
 
Ashish PatelCommented:
Try changing, though your code seems working for me.
cats.sort();
to
cats = cats.sort();
0
 
Aneesh ChopraCommented:
cats.sort() is working fine in your code,
problem is that you are tracing the part3 using "for in" loop which does not gets effected with Array.sort();
you should use "for()" loop

here is the fixed code and it works fine:

function layout()
{
	var cats = ["40artist", "30still", "50fashion"];
	trace("---- Part 1: "+cats);
	cats.sort();
	trace("---- Part 2: "+cats+"\n");
	for (var i = 0; i<cats.length; i++)
	{
		trace("---- Part 3: "+cats[i]);
	}
	trace("\n---- Part 4: "+cats+"\n");
}
 
layout();

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0
 
Aneesh ChopraCommented:
If you have to have "for in" sorting then you can do it with using an extra temp Array

here is the code which will do the trick for you
function layout()
{
	var cats = ["40artist", "30still", "50fashion"];
	trace("---- Part 1: "+cats);
	cats.sort();
	trace("---- Part 2: "+cats+"\n");
 
	var tmp_arr = [];
	for (var i = 0; i<cats.length; i++)
	{
		tmp_arr.push(cats[i]);
	}
	cats = tmp_arr;
	for (var i in cats)
	{
		trace("---- Part 3: "+cats[i]);
	}
	trace("\n---- Part 4: "+cats+"\n");
}
 
layout();

Open in new window

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